The present invention relates to a building and a door assembly mounted therein and, more particularly, to a building and a bi-fold door assembly coplanar with the walls thereof.
In recent years, the use of out buildings for storage has expanded to a very significant degree. Such buildings have found use, for instance, as hangars to accommodate the considerable expansion in the use of small aircraft for both business and pleasure with the resulting problem of providing adequate shelter at a reasonable price and for storage of large equipment such as farm machinery, earth moving equipment, large trucks and the like. As a result, the need for buildings having large doors which operate safely, effectively and efficiently has been the focus of those in this field.
Some years ago, Erect-A-Tube, Inc., our assignee, pioneered the development of a unique bi-fold door. These doors, which are quite large in size ranging to at least 80 feet wide 20 feet high, have become standard. It is now recognized that the bi-fold door gives rugged, dependable service and is reliable and easy working in almost every climatic condition. These doors, which are easy to install on post-frame or steel buildings, can be sheeted and insulated with conventional building materials. As such, the bi-fold doors give extra clearance for large openings and are compatible with all metal building systems.
In the past, bi-fold doors have been constructed so that the upper and lower door sections are coplanar. The door, which usually includes two co-planar door sections which are horizontally hinged, generally includes means on the bottom of the lower door portion to cooperate with a door track. As a result, the bottom of the door moves straight up from the floor to minimize the effect of snow and ice on the opening action.
Despite the numerous significant advantages to a bi-fold door, several problems have remained unresolved. One problem has been that snow and ice can sometimes build up at the base of the door to restrict the opening action and/or make it necessary for snow removal to eliminate frozen door problems. In particular, where there is frequent thawing and freezing, ice can build up at the bottom of the door thereby causing the door to stick in the down position.
When this occurs, it is oftentimes very difficult to remove the ice. It has also been the case that, when there is a buildup of snow at the bottom of the door, drivers of snow plows at airports and the like have damaged such doors by attempting to clear the snow without manual labor. Further, since metal building systems usually do not have gutters and down spouts, it is difficult to keep water from passing under the door.
Still another problem with bi-fold doors has been the difficulty in assuring that the door fully closes when it is lowered. This is absolutely essential to provide the requisite security as well as to fully protect the contents of the building from weather conditions. Because of the fact that vertical door tracks are the norm in such buildings, and the uniqueness of the configuration of the door, the bi-fold door can have a tendancy to stick in a partially opened condition.
Accordingly, it has remained to provide a building and a bi-fold door that overcomes the problems outlined.